Rick,
See my reply to another message. TMG is not the only program that allows for
multiple roles, customized sentences or unlimited witnesses. If the data
could be transferred, it would have a place. GEDCOM just can't transfer it.

You're absolutely right that "any software developer could add the
features...". The fact, though, is that they haven't. Therefore, there
remains no place to put the Witness/Role, etc., data even if it could be
exported from TMG. So in that context also, exporting that data from TMG
is also a dead end.